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From: grog@lemis.de (Greg Lehey)
Organisation: LEMIS, Schellnhausen 2, 36325 Feldatal, Germany
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Reply-To: grog@lemis.de (Greg Lehey)
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Subject: Re: linux' mknod and named pipes.
To: bde@zeta.org.au (Bruce Evans)
Date: Sat, 18 Nov 1995 11:28:45 +0100 (MET)
Cc: hackers@freebsd.org (FreeBSD Hackers)
In-Reply-To: <199511180923.UAA17204@godzilla.zeta.org.au> from "Bruce Evans" at Nov 18, 95 08:23:52 pm
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Bruce Evans writes:
> 
> >> >Is there any good reason why we shouldn't modify mknod to make a fifo
> >> >when called with the appropriate parameters?
> >> 
> >> The same reason we shouldn't modify thousands of other system calls to be
> >> compatible with thousands of other systems: it takes longer and gives
> >> worse results.
> 
> >I think that bears discussion.
> 
> >1.  It takes longer:
> 
> >--- vfs_syscalls.c      1995/11/14 09:19:16     1.40
> >+++ vfs_syscalls.c      1995/11/18 08:45:43
> >@@ -757,6 +757,13 @@
> >        int error;
> >        struct nameidata nd;
> > 
> >+       if (ISFIFO (uap->mode))
> >+         {
> >+         struct mkfifo_args args;
> >+         args.path = uap->path;
> >+         args.mode = uap->mode;
> >+         return mkfifo (p, args);
> >+         }
> >        error = suser(p->p_ucred, &p->p_acflag);
> >        if (error)
> >                return (error);
> 
> >    OK, I haven't tested this, but it's got to be something like it.
> >    In the normal case, there's a single 'if' involved.
> 
> It takes longer to write, document, commit and test.  Perhaps even as
> long as to argue about it :-).

Nah, never!

> >2.  It gives worse results.  How?  Why?
> 
> It just confuses programmers to have two ways of doing the same thing.

Not if you say "this feature is deprecated and only exists for
compatibility with obsolescent operating systems".

> The p flag to mknod(8) isn't supported either.

Don't let me ask why not :-)

Greg